Stabilizing mechanism

ABSTRACT

A mass is supported in a frame free from gravitational influence by spring means so that translatory frame movement of low frequency will be transmitted to said mass while translatory frame movement at or above a predetermined high frequency will be isolated from said mass. The spring means defines a pair of intersecting axes about which the mass is adapted to vibrate when the spring tensions because of high frequency translatory frame movements. Magnetic means, however, resist return of the mass to a balanced condition from an unbalanced condition which the mass assumes when the spring is tensioned, thereby to lower the inherent vibratory frequency of the mass to a value below the predetermined high frequency.

Gross........

Primary Examiner.l. Franklin Foss Attorney, Agent, or Firm-John L. Cline[57] ABSTRACT A mass is supported in a frame free from gravitationalinfluence by spring means so that translatory frame movement of lowfrequency will be transmitted to said mass while translatory framemovement at or above a predetermined high frequency will be isolatedfrom said mass. The spring means defines a pair of inter- 350/ l 6 G02b23/02 secting axes about which the mass is adapted to vibrate when thespring tensions because of high fre- 74/5 F; quency translatory framemovements. Magnetic means, however, resist return of the mass to abalanced condition from an unbalanced condition which the mass assumeswhen the spring is tensioned,

thereby to lower the inherent vibratory frequency of the mass to a valuebelow the predetermined high frequency.

11 Claims, 9 Drawing Figures Inventors: James Reekie, Arcadia, Calif;

Marvin F. Royston, Skokie, 111.

Assignee: Bell 82 Howell Company, Chicago,

Filed: Nov. 4, 1971 Appl. No: 195,879

Related US. Application Data Continuation of Ser. No. 831,974, June 10,1969, abandoned.

U.S. 248/358 R,

References Cited UNlTED STATES PATENTS 9/1954 Jensen ilnite StatesPatent Reelrie et a1.

1 1 STABllLlZlNG MECHANISM [58] Field of Search...........

a A P m w 4/1958 Jensen............. 7/1958 Werner........... 3,013,46412/1961 Keuffel et a1.

STABILIZING MECHANISM This is a continuation of application Ser. No.831,974 now abandoned, filed June 10, 1969 by express abandonment.

The present invention relates to stabilizing mechanisms. Particularly,the invention relates to means for filtering out high frequency angularmotions, while at the same time passing or transmitting motions of lowfrequency. Specifically, the invention is adapted for, but not limitedto, stabilization of optical instruments, such as cameras and binocularsof the type which are ordinarily hand-held when used.

In optical systems having a stabilizer, a coupling or mount connects alens (a mass with a high moment of inertia) with a frame fortransmitting translatory frame movement of low frequency to, whileisolating high frequency translatory frame movement from, the lens. As aresult, a field of view of a hand-held instrument can be changed bymoving the frame, in a customary manner for that purpose, inasmuch assuch movement is of low frequencysln contrast, normal trembling handmotion, being of high frequency, will be filtered out or isolated fromthe lens to prevent movement.

Heretofore known stabilizers of the indicated type may be divided intotwo classes. A first, exemplified by U.S. Pat. No.'3,25 l ,262, ischaracterized in that a lens is pendulously mounted in its casing or.frame, relying on gravitational influence, to produce desired orientation. The other, the class with which the present invention isconcerned, is characterized in that a mass of high inertial movement isindependent of gravitational influence and tends to assume a fixed orbalanced relationship with respect to a frame in which it is mounted. Itis exemplified by US Pat. No. 2,688,456.

In heretofore known devices of the last mentioned class, a gimbalcouples the mass and frame to enable movement of each mass aboutintersecting axes. While such mechanisms are satisfactory in effectingstabilization. the cost of providing required fine bearings limits theirwidespread use. Particularly, in popularly priced cameras andbinoculars, and the like, use of heretofore known stabilizing mechanismsis unknown.

It is an object of the present invention to provide an improvedstabilizing mechanism.

It is another object of the invention to provide a stabilizing mechanismenabling translatory frame movements of low frequency readily to betransmitted to a mass for moving the latter with the frame, whileisolating high frequency angular movement of the frame from the mass.

It is a further object of the invention to provide in opticalinstruments such as cameras and binoculars, a means for stabilizing alens system against high frequency translatory frame movement which willbe efficient in use, durable and which can be produced for a reasonablecost.

Yet further. it is an object of the invention to provide an improvedoptical device.

An additional object of the invention is provision of improved binocularconstruction.

Moreover, it is an object of the invention to provide an improved cameraconstruction.

To effect the foregoing objects, for a mass with a high movement ofinertia, there is provided elastic means in a stabilizing mechanism to:(a) balance the mass against gravitational influence, and in a fixedcondition for movement relative a frame; and (b) constrain the mass formovement with said frame when said frame is moved angularly at lowfrequency. The elastic means are connected to the frame and tensionallysupport the mass for harmonic-like movement about a pair of axes whenthe rate of translatory frame movement is at a high frequency.

Further and other objects of the invention will be apparent from thedescription of the accompanying drawings, in which like numerals referto like parts.

In the drawings:

FIG. 1 is a perspective of one embodiment of the invention, incorporatedin a camera, parts of which have been broken away;

FIG. 2 is a sectional view taken on the lines 2-2 of FIG. 1;

FIG. 3 is a top plan of an embodiment of the invention modified fromFIG. 1 and incorporated in a camera shown partially, in section;

FIG. 4 is a perspective of yet another embodiment of said inventionincorporated in a camera, parts of which are broken away;

FIG. 5 is a perspective of elastic means of yet another embodiment ofsaid invention;

FIG. 6 is a perspective of a modification of the invention embodied inbinoculars, portions of which have been broken away;

FIG. 7 is a sectional view taken on the lines 77 of FIG. 6;

FIG. 8 is a detailed sectional view taken .on the lines 8-8 of FIG. 7;and

FIG. 9 is a sectional view taken on the lines 9-9 of FIG. 6.

Referring now more particularly to FIG. 1, a stabilizing mechanismgenerally designated 10 is adapted for an optical instrument such as acamera having an outer housing or casing shown in dashed lines andreferred to generally as frame 12. The mechanism is adapted to balance amass 14 with a high moment of inertia against gravitational influenceand in a fixed condition for movement relative said frame whentranslatory frame movement having certain angular characteristics is ofhigh frequency. Moreover, the mechanism is adapted for transmittingtranslatory frame movements to said mass for its movement with saidframe when the rate of such movement, in selected angular directions, isof low frequency.

Elastic means, herein shown as spring 16, has a frame proximate portion15 and a portion 17 opposed thereto. Spring portion 15 is connected toframe 12 through the agency of a block 13 (shown in phantom) which isfixed to said frame. The mass is supported from portion 17 and therebycoupled to the frame for harmonic-like movement about a pair of axes Yand P, when the rate of translatory frame movement is at a highfrequency.

For the various illustrated devices, low frequencies are less than abouta half cycle per second, while high frequencies are upwards of one cycleper second. The customary vibratory rate of trembling human hands in inthe range of l to 20 cycles per second. Angular motion of high frequencydesired to be isolated from the illustrated optical systems are yaw-like(about vertical axis Y) and pitch-like (about horizontal axis P). Highfrequency roll-like motions about horizontal axis R, which defines thefixed optical axis of the systems shown in FIGS. 1, 3 and 4 are of noconsequence, be cause they do not change the distance of the lenscomprising mass 14 from a subject with respect to which a system isnormally oriented during use.

Spring 16 defines the Y and P axes which intersect in said spring at apoint 25 about which the mass 14 is adapted to move relative to saidframe through the agency of an elongated mount generally designated 18.The spring is fashioned for vibratory movement about the P and Y axes,respectively. In consequence. point 25 comprises the center of movementof mass 14. A medial section 19 of said mount is rigidly secured tospring portion 17, and a pair of mount projections or extensions 20 and22 extend in opposite directions from medial section 19. Mass 14 issecured from an outer end portion of extension 20.

In each of the embodiments of FIGS. 1, 2 and 3, mass 14 comprises amovable convex lens or optical wedge 24 whose center of curvature isdefined by point 25. A concave lens 26 is fixed to frame 12 as theforward element of the optical system in each of FIGS. 1, 3 and 4, in amanner such that the optical centers of lenses 24 and 26 are disposed onaxis R when the parts are not in motion. The center of curvature of lens26 also is point 25, and said lens is slightly spaced from lens 24 andtherewith forms a doublet.

In consequence of the foregoing arrangement, adjoining faces of lenses26 and 24 are concentrically disposed so that upon their relativemovement they will remain uniformly spaced at all positions of relativeangular movement. Further comprising the optical systems of FIGS. 1, 3and 4, however, omitted from FIG. 4 to minimize crowding of the view, isa focusing lens 28 fixed in frame 12 by any suitable means, between lens24 and the focal plane of the camera. Lens 28 is centered about axis Rfor impinging an image on frame 30 of filmstrip 32 carried in said focalplane.

To limit relative movement between mass 14 and frame 12, an abutmentmember 34 is secured to the frame and has an opening 36 through whichmount 18 loosely extends. A coun terwieght 40, (omitted from FIGS. 1 and4) is adjustably mounted for movement longitudinally of section 22 ofmount 18 for effecting a condition in which mass 14 is balanced in orfixed relative to frame 12 at any fixed angular aspect of said frame.That balancing is effected by moving the center of gravity of the totalsuspended mass to a point coincident with the intersection of axes P andY.

While mounts 18 of FIGS. 1 and 3 are mechanical equivalents. mountsections 20 and 22 in FIG. 1 are shown aligned and disposed on a commonside of spring 16. An arm 42, fashioned integrally with said mountprojects normally from the juncture of said sections and is rigidlysecured to spring end portion 17. In FIG. 3, sections 20 and 22 areparallel. being disposed on opposite sides of spring 16. An integralmedial mount portion 44, which itself is rigidly secured to spring 16,connects said sections.

In the embodiment of FIGS. 1 and 3, spring 16 is fashioned as a bandwhich projects normally away from its position of securance to frame 12.The spring has a longitudinally extending medially disposed rigidifyingwelt or rib 46 (FIG. 2) fashioned for limiting rotation of mass 14 aboutdesired axes.

In FIG. 4, the equivalent of mount 18 is an elongated structure 48 ofcage-like fashioning. It has a pair of oppositely extending end sections50 and 52 which are equivalent to sections 20 and 22. A ring 54 centeredabout the optical axis of lens 26 defines a medial section of saidmount. A pair of diametrically opposed straps 56 and 58 which comprisestructure 48 are integral with said ring and extend transverselythereof. The ring distal end portions of straps 56 and 58 which definesection are secured to opposite sides of lens 24. The portions of saidstraps which form section 50 also project through a ring 60 which isdisposed between lens 24 and ring 54, said ring 60 being slightly spacedfrom ring 54 and concentric with the optical axis.

Four radial extensions 62, 64, 66 and 68 are disposed angularly fromeach other 90 and define two sets which are disposed normally to eachother and project outwardly from ring 60. The set comprising extensions64 and 68 are secured to frame 12 through the agency of a pair ofparallel flat springs 70 and 72 which define a plane. The latter areband-like and each has an end secured to corresponding of extensions 64and 68. Each of said springs has an opposite end secured to acorresponding of a pair of blocks 74 and 76 which themselves are fast toframe 12. The arrangement is such that springs 70 and '72 define an axisfor pitch-like movement of the frame.

A pair of flat springs 78 and 80 in the form of bands have commonlydirected ends connected to the set comprised of extensions 62 and 66,respectively, and oppositely directed ends which are secured to arespective of a pair of extensions 82 and 84. The latter projectdiametrically outwardly from ring 54 in alignment with extensions 62 and66, respectively, to define the Y axis about which lens 24 is movable ina yaw-like mode. Springs 78 and 80 lie in a common plane normal to theplane in which springs 70 and 72 are disposed; and all of said springsextend longitudinally of the longitudinal axis of mount 48, parallel tothe optical axis and to each other and comprise elastic means ofgimbal-like character equivalent to spring 16.

In the embodiment of FIG. 5, the elastic means comprises a flat annularmember 84 having four radial springs 86, 88, and 92, fashioned as spokesor flat bands which are shortened by omitting their center sections. Thesprings are disposed in a common plane and have outer wide sectionswhich are integrally fashioned with the annular periphery of member 84.The springs are arranged in diametrically spaced apart sets or pairs,said sets or pairs being normal to each other. The inner narrow ends ofsaid springs are rigidly secured to a ring 94, which is centered aboutoptical axis R and disposed within and concentric with the outerperiphery or annulus of member 84. Ring 94 comprises a medial section ofan elongated mount for lens 24, the opposite end sections of suchsupport having been omitted from FIG. 5. At diametrically opposedpositions in alignment with the set comprised of springs 86 and 90, theouter annulus of member 84 is anchored by a pair of suitable fastenersto frame 12.

Member 84 is disposed at an angular aspect about optical axis R andfashioned in a manner such that springs 86 and 90 define the P axis,while spring members 88 and 92 define the Y axis.

The construction and arrangement of the member 84 as well as spring 16and its equivalent of FIG. 4 is such that all angular frame movement,regardless of frequency, about optical axis R, will be transmitted tomass 24. However, each elastic means will become tensioned upon angularframe movement of high frequency about the Y and P axes, in consequenceof which its associated mass will tend to vibrate at an inherentfrequency about the spring or springs comprising such elastic means. Thetensioning results from the inertia induced tendency of the mass toremain station. ary despite frame movement.

Means generally designated 96 are provided for resisting the tendency ofthe mass to vibrate at its inherent period and provide a long normalperiod and low frequency for the system. The definition of low" and highfrequencies will vary from one application to another. As previouslynoted in a movie camera application high means one cycle per second andabove, and low" means anything below one cycle per second. The resistingmeans may be spring-like in character. In the illustrated embodiments,the resisting means comprises a pair of permanent magnets herein shownin alignment. A first magnet 98 is rigidly secured to its respectivemount in a position which may, but not necessarily need be, opposed frommass 14. The other magnet 100 of each pair is rigidly secured to frame12. As illustrated in FIGS. 1 and 4, a bracket 102 which is secured tosaid frame may be employed for holding magnet 100.

Magnets 98 and 100 are slightly spaced each from the other, with likepoles in facing association. Moreover, the arrangement of the magnets issuch that the repelling force generated in the magnetic field does notsignificantly displace the mass from its balanced or fixed condition,i.e., when the elastic means is untensioned.

However, the magnets are proportioned and arranged in a fashion suchthat once the elastic means is tensioned, that is to say, once theoptical axis of lens 24 is displaced from its fixed condition orbalanced condition along axis R to an unfixed or unbalanced conditionalong axis R (FIG. 3), the magnetic field will resist the tendency ofthe mass to vibrate around axes Y and P, and the mass will slowly returnat a low frequency to its balanced position and thereby minimize anydistortions due to relative vibrations of lens 24 and a field on whichthe camera is trained. Accordingly, translatory vibrations of highfrequency imposed on frame 12 are effectively isolated from lens 24 andwill only slightly affect it. It is appreciated that the vibrationresisting force of the magnetic field when the magnets are disalignedcan be adjusted according to size, spacing and magnetic characteristicsof said magnets.

A caging mechanism generally designated 104 (FIGS. 1 and 6) has beenomitted from FIGS. 3 and 4. It is arranged for locking the mass in itsfixed or balanced position when the apparatus in connection with whichsuch caging mechanism is employed is not in use. To that end, anelongated pin or plunger 106 is mounted for slidable movementlongitudinally of its axis. The plunger has a tapered head 108 on itsinner end to facilitate entry into an aligned receiving hole or seat 110in the mount for the mass. A bracket 112, which is fixed to frame 12,slidably supports plunger 106 with head I08 normally disposed in thehole 110 to lock the mount to the frame. Means for urging the pin intoits normal condition comprises a coil spring 114 which is mounted aboutthe pin with its opposite ends bearing against a collar 116, carried onsaid pin, and an arm 118 of bracket 112. The pin is arranged so that aprojection of its longitudinal axis intersects center 25, therebyprecluding tensioning of the elastic means when the caging mechanism isin locking conditron.

An extension 120 of said pin slidably projects outwardly through arm 118and engages a manually rockable control member 122 which is disposedabout said extension between bracket arm 118 and a limiting collar 124secured on the outermost end of said arm. Control member 122 ispivotably mounted for movement about an axis pin 126 between its normalor caged condition to which it is drawn by spring 114 and a tensionedcondition in which it is limited by adjustable stop 128 to unseat head108 from hole 110 and liberate the mount. A manual component 130disposed outside of frame 12 is arranged to rock control member 122 forwithdrawing head 108 against tension of spring 114.

The invention is also adapted for binoculars 132 (FIG. 6), here showncomprising housing means defining a pair of lens barrels or compartments136 and 138 in the forward ends of which there are mounted a pair oflenses 140 and 142. An outer hand grippable structure, casing or shroudcomprises a frame 144 which may be of less mass than the binocularsandis disposed about said housing means.

Elastic means comprising spring 16 is connected to frame 144through theagency of a block 146. The latter is fast to the frame and disposedbetween compartments 136 and 138. A clamp 148 fastens spring 16 to block146 by suitable fasteners such as screws. In FIG. 6, the opposite end ofspring 16 is clamped to a boss 150. A mount or coupling 152 isadjustably secured to said boss by a screw 168 for connection to saidspring.

Coupling 152 is an elongated member extending longitudinally of theoptical axes of lenses 140 and 142 for vibratably supporting the housingmeans relative to frame 144, independent of gravitation influence. To

that end, an extension 154 from a medial part of said coupling isrigidly connected to the housing through the agency of a connecting rod156, which is parallel to coupling 152 and disposed between compartments136 and 138. Opposite ends of said connecting rod are connected to apair of parallel ties 158 and 161, which are disposed transversely ofrod 156 for coupling the binocular compartments 136 and 138 together inspaced-apart relationship. As illustrated, each crosspiece may be anassembly of conventional design of a pair of overlapped extensionsarranged from said compartments to permit rocking of one compartmentrelative the other about an axis defined by rod 156 to vary compartmentspacing.

From the foregoing, it is seen that the binoculars 132 comprise a masswhich is hung from spring 16 through the agency of mount or coupling 152and said binoculars is mechanically equivalent to mass 14 heretoforedescribed.

Extension 154 has a hole 160, distal coupling 152 and into which a pin162 of smaller diameter than said hole projects. The pin is carried froma bracket or block 164 which is rigidly secured to the frame 144. Thewall, defining hole 160, thereby limits movement of binoculars 132 andcoupling 152 relative to frame 144.

To balance coupling 152 in a fixed or normal condition relative to frame144 free from gravitational influence, boss has a slot 166 in whichscrew 168 is ad- 65 justably disposed for releasably securing saidcoupling manent magnets 170 and 172 which are coaxially aligned and havelike poles in facing and slightly spaced association one from the otherwhen the mass is wholly balanced or in its fixed position. Magnet 170 iscarried in a block 174 which is secured by suitable means to frame 144.Magnet 172 projects outwardly from an end section 176 of coupling 152.Magnets 170 and 172 are proportioned and arranged for holding coupling152 in its balanced condition, but for resisting return to said balancedcondition once it is upset. Thereby high frequency movement ofbinoculars 132 is precluded when frame 144 is moved at a high frequency.

Coupling 152 can be fashioned to accommodate caging mechanism 104 byproviding a cutout 178 into which portions of the caging bracket extend.A hole 180 (FIG. 7) provided in coupling 152 defines a seat for head 108of said caging mechanism. A control member corresponding to member 122has been omitted from FIG. 6 to minimize obscuring of other essentialdetail.

Although magnetic means 96 is effective for frequency control of themass, a suitable damping agent 182 (FIG. 6) for controlling amplitude ofoscillations also may be provided. The exemplary damping agent comprisesa viscous damping mass in the form of a silicon rubber band which hasone end anchored on frame 144 and its opposite end anchored on couplingextension 154.

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and detail may bemade therein without departing from the spirit and scope thereof.

What is claimed is:

l. A stabilized mass system comprising:

a frame member;

a mass;

elastic means mounting said mass to said frame member for vibrationabout an axis at an inherent vibratory frequency;

said mounted mass having a rest position relative to said frame memberand said elastic means applying a return torque to said mounted mass toreturn said mounted mass to said rest position when said mounted mass isdisplaced from said rest position, said return torque beingsubstantially zero when said mounted mass is at said rest position andincreasing in magnitude as said mounted mass is displaced from said restposition; and

means for applying a torque to said mounted mass in opposition to saidreturn torque, said opposing torque being substantially zero when saidmounted mass is at said rest position and increasing in magnitude assaid mounted mass moves away from said rest position during saidvibratory motion about said rest position. thereby reducing saidinherent vibratory frequency of said mounted mass.

2. A mass system stabilized with respect to a frame during vibration ofsaid frame that comprises:

a frame capable of being vibrated;

a band spring mounting a mass system to said frame for rotation about anaxis;

a first magnet mounted on said mass system; and

a second magnet mounted on said frame;

said first and second magnets being disposed such that when the masssystem is at rest like magnetic poles are in facing relationship andsuch that they apply a torque to said mounted mass in opposition to saidspring and, said opposing torque being substantially zero when saidmounted mass is at said rest position and increasing in magnitude assaid mounted mass moves away from said rest position during saidvibratory motion about said rest position, thereby reducing saidinherent vibratory frequency of said mounted mass. I

3. A system for stabilizing a mass connected to a frame during vibrationof said frame at or above a high frequency comprising:

a frame member capable of being vibrated at or above a predeterminedhigh frequency; a mass; elastic means mounting said mass to said framefor vibration about an axis, said mounted mass having a high vibratoryfrequency; and

means for applying a torque to said mounted mass in opposition to saidelastic means, said opposing torque being substantially zero when saidmounted mass is at said rest position and increasing in magnitude assaid mounted mass moves away from said rest position during saidvibratory motion about said rest position, thereby reducing saidinherent vibratory frequency of said mounted mass.

4. A system for stabilizing a mass mounted to a member during vibrationof the member at or above a predetermined high frequency about a pair ofsubstantially intersecting axes comprising:

a member capable of being vibrated at or above said high frequency;

a mass system;

elastic means mounting said mass system for vibratory movement aboutsaid pair of substantially intersecting axes;

said mounted mass system having an inherent harmonic vibratory frequencyabout each of said axes at least as high as said predetermined highfrequency;

said mounted mass system being so disposed that the center of gravitythereof is substantially coincident with the point of intersection ofsaid axes when said mounted mass system is in equilibrium position withrespect to said member; and

modifying means for applying a torque to said mounted mass in oppositionto said elastic means, said opposing torque being substantially zerowhen said mounted mass is at said equilibrium position and increasing inmagnitude as said mounted mass moves away from said equilibrium positionduring said vibratory motion about said equilibrium position, therebyreducing said inherent vibratory frequency of said mounted mass.

5. The system set forth in claim 4, wherein said modifying meanscomprises a first magnet mounted on said mass system and a second magnetmounted on said frame. said magnets being disposed such that when saidmass system is at rest like poles face one another.

6. The system set forth in claim 4 wherein said elastic means is a bandspring having one end fixed to said frame and the other end fixed tosaid mass system, said spring being capable of flexure about both thelongitudinal axis of said spring and a second axis that is perpendicularto and intersects said longitudinal axis.

7. The system set forth in claim 6 wherein said modifying meanscomprises a first magnet mounted on said mass system and a second magnetmounted on said frame, said magnets being disposed such that when saidmass system is at rest like poles face one another.

8. The system set forth in claim 4 wherein said elastic means comprisesa first pair of band springs mounted at one end to said frame and at theother end to a ring for flexure about a first axis; and a second pair ofband springs mounted at one end to said ring and at the other end to theremainder of said mass system for flexure about a second axis.

9. The system set forth in claim 8 wherein said modifying meanscomprises a first magnet mounted on said mass system and a second magnetmounted on said member, said magnets being disposed such that when saidmass system is at rest like poles face one another.

said mass system is at rest like poles face one another. l =l

1. A stabilized mass system comprising: a frame member; a mass; elasticmeans mounting said mass to said frame member for vibration about anaxis at an inherent vibratory frequency; said mounted mass having a restposition relative to said frame member and said elastic means applying areturn torque to said mounted mass to return said mounted mass to saidrest position when said mounted mass is displaced from said restposition, said return torque being substantially zero when saId mountedmass is at said rest position and increasing in magnitude as saidmounted mass is displaced from said rest position; and means forapplying a torque to said mounted mass in opposition to said returntorque, said opposing torque being substantially zero when said mountedmass is at said rest position and increasing in magnitude as saidmounted mass moves away from said rest position during said vibratorymotion about said rest position, thereby reducing said inherentvibratory frequency of said mounted mass.
 2. A mass system stabilizedwith respect to a frame during vibration of said frame that comprises: aframe capable of being vibrated; a band spring mounting a mass system tosaid frame for rotation about an axis; a first magnet mounted on saidmass system; and a second magnet mounted on said frame; said first andsecond magnets being disposed such that when the mass system is at restlike magnetic poles are in facing relationship and such that they applya torque to said mounted mass in opposition to said spring and, saidopposing torque being substantially zero when said mounted mass is atsaid rest position and increasing in magnitude as said mounted massmoves away from said rest position during said vibratory motion aboutsaid rest position, thereby reducing said inherent vibratory frequencyof said mounted mass.
 3. A system for stabilizing a mass connected to aframe during vibration of said frame at or above a high frequencycomprising: a frame member capable of being vibrated at or above apredetermined high frequency; a mass; elastic means mounting said massto said frame for vibration about an axis, said mounted mass having ahigh vibratory frequency; and means for applying a torque to saidmounted mass in opposition to said elastic means, said opposing torquebeing substantially zero when said mounted mass is at said rest positionand increasing in magnitude as said mounted mass moves away from saidrest position during said vibratory motion about said rest position,thereby reducing said inherent vibratory frequency of said mounted mass.4. A system for stabilizing a mass mounted to a member during vibrationof the member at or above a predetermined high frequency about a pair ofsubstantially intersecting axes comprising: a member capable of beingvibrated at or above said high frequency; a mass system; elastic meansmounting said mass system for vibratory movement about said pair ofsubstantially intersecting axes; said mounted mass system having aninherent harmonic vibratory frequency about each of said axes at leastas high as said predetermined high frequency; said mounted mass systembeing so disposed that the center of gravity thereof is substantiallycoincident with the point of intersection of said axes when said mountedmass system is in equilibrium position with respect to said member; andmodifying means for applying a torque to said mounted mass in oppositionto said elastic means, said opposing torque being substantially zerowhen said mounted mass is at said equilibrium position and increasing inmagnitude as said mounted mass moves away from said equilibrium positionduring said vibratory motion about said equilibrium position, therebyreducing said inherent vibratory frequency of said mounted mass.
 5. Thesystem set forth in claim 4, wherein said modifying means comprises afirst magnet mounted on said mass system and a second magnet mounted onsaid frame, said magnets being disposed such that when said mass systemis at rest like poles face one another.
 6. The system set forth in claim4 wherein said elastic means is a band spring having one end fixed tosaid frame and the other end fixed to said mass system, said springbeing capable of flexure about both the longitudinal axis of said springand a second axis that is perpendicular to and intersects saidlongitudinal axis.
 7. The system set forth in claim 6 wherein saidmodifyinG means comprises a first magnet mounted on said mass system anda second magnet mounted on said frame, said magnets being disposed suchthat when said mass system is at rest like poles face one another. 8.The system set forth in claim 4 wherein said elastic means comprises afirst pair of band springs mounted at one end to said frame and at theother end to a ring for flexure about a first axis; and a second pair ofband springs mounted at one end to said ring and at the other end to theremainder of said mass system for flexure about a second axis.
 9. Thesystem set forth in claim 8 wherein said modifying means comprises afirst magnet mounted on said mass system and a second magnet mounted onsaid member, said magnets being disposed such that when said mass systemis at rest like poles face one another.
 10. The system set forth inclaim 4 wherein said elastic means comprises two pair of diametricallyopposed springs that are mounted at one end to said frame and at theother end to said mass system for flexure about said pair of mutuallyperpendicular intersecting axes.
 11. The system set forth in claim 10wherein said modifying means comprises a first magnet mounted on saidmass system and a second magnet mounted on said member, said magnetsbeing disposed such that when said mass system is at rest like polesface one another.